"I don't have to demonstrate anything," argued Ronaldo, who recently scored 11 goals in seven internationals, including a hat-trick against Sweden that secured his side's qualification. "Not now or before or after. What I have to do is continue my career which has been great so far.

Ronaldo scored a hat-trick against Sweden that secured Portugal's qualification

"I believe one player is not a team, I'm here in the national team to help, I'm an additional player, I can make a difference in some of the games, but I can't carry the whole team on my back.

"I'm just someone who wants to help to become a champion. We're not the favourite or in the group of favourites, which is something which is good for us."

Ronaldo took a full part in the 15 minutes of Portugal's training session that was open to the media inside Arena Fonte Nova.

There was strapping below his left kneecap, but he appeared to be comfortable and with a full range of movement.

Concern was raised when the former Manchester United player arrived more than an hour late for his scheduled news conference, but he quickly dismissed any worries.

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"I've been practising now for some days and if I'm doing that it's because I'm feeling well," he added. "Obviously I would like to not have any pain but that's impossible.

"Since I've played football there's not been one single moment when I played a match without any pain whatsoever. That's just part of it, it's the burden of my work.

"If I'm not ready, if I'm not feeling well, I'm the first to tell the coach I can't play.

"The first thing that is important is the health of the players. If I feel anything during the match, which I'm sure I won't, I'll be the first to say, as I know my career will still last a few years and I'm never going to put at risk my career for one match or for the World Cup.

"Obviously this is one of the most important championships but I come first, and then football."